Like It Or Not, All Americans With A Cellphone Will Receive A Text Message From President Trump At Approximately 2:18 P.M.

NEW YORK (CBSNewYork) — Americans nationwide will receive an alert on their cellphones from President Donald Trump for the first time ever Wednesday.

It’s the first test of a national presidential alert system that will let the president issue a warning about a crisis. That could include a missile launched by another country at the U.S., or a tsunami, CBS2’s Chris Wragge reported Tuesday.

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It’s the alert that — if it’s real — you won’t want to get again.

“When those messages appear on mobile devices, people should take those extremely seriously. It has some direct impact on either life or safety,” said Antwane Johnson of the Federal Emergency Management Agency.

Johnson directs the agency’s public alert warning system.

“If we have something that’s of national significance, we can rapidly notify the American public of that event,” Johnson said.

President Trump was scheduled to send a text message to all Americans with a cellphone on Oct. 3, 2018. (Photo: CBS2)

Government agencies nationwide have issued more than 40,000 emergency alerts to cellphones since 2012. But those AMBER and weather alerts target specific regions. This new presidential alert will be nationwide, and only used for advance warning of national crises.

“It should be reserved for true situations, true emergencies, when we need to get the public’s attention,” said Jeh Johnson, the former secretary of Homeland Security.

Jeh Johnson it is designed to be used very specifically — and rarely.

“This is something that should not be used for a political agenda,” he said.

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Jeh Johnson said that’s especially important because no one can opt out of these alerts.

Still, some worry the president will use the alerts much as he does with his Twitter account, all the time.

“No, not at all,” Antwane Johnson assured. “One thing that we need make very clear is that there are laws, policies and procedures that are in place, other protocols to assure the system is used in accordance with its intended use as defined by the law.”

What if Trump wanted to send an alert that didn’t fit the criteria?

“I would say that the protocols would certainly guide him down a path that may steer him actually away from sending that message that does not fit the criteria,” Antwane Johnson said.

Alerts are not foolproof, however. In January, Hawaii’s emergency management agency mistakenly sent out an alert to more than 1 million cellphones warning of a ballistic missile threat.

Mistakes like that could make people nervous about this new nationwide alert, says Andy Whitehouse, who teaches communications at Columbia University.

“The fact that you can’t turn this alert off, that it will be something that will arrive on your phone whether you like it or not I think was perhaps upsetting and concerning to some people,” Whitehouse said.

The test is scheduled for Wednesday at 2:18 p.m.

Three New Yorkers filed a federal lawsuit last week attempting to block the test, saying it violates free speech and is an unconstitutional seizure of electronic devices.

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The test will set off the same loud sound used for other alerts. If your cellphone is on and you have service, you will likely receive it and you will not be able to stop it.